docs: def fieldinfo(self):
          """Retrieve info about all vdata fields.
  
          Args::
  
            no argument
  
          Returns::
  
            list where each element describes a field of the vdata;
            each field is described by an 7-element tuple containing
            the following elements:
  
            - field name
            - field data type (one of HC.xxx constants)
            - field order
            - number of attributes attached to the field
            - field index number
            - field external size
            - field internal size
  
          C library equivalent : no equivalent
                                                        """
  
          lst = []
          for n in range(self._nfields):
              fld = self.field(n)
              lst.append((fld._name,
                          fld._type,
                          fld._order,
                          fld._nattrs,
                          fld._index,
                          fld._esize,
                          fld._isize))
  
          return lst